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4 years ago

Calculate the moles of Cu in 7.4×1021 atoms of Cu.

1 answer:

5 0

1 moles -------- 6.02x10²³ atoms
?? moles ----- 7.4x10²¹ atoms

moles = 7.4x10²¹ / 6.02x10²³

= 0.01229 moles

hope this helps!

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Which elements have the quantum numbers (4,3,-2,+1/2) and (5,2,-1,-1/2)

nikklg [1K]

The elements are samarium (Sm) and silver (Ag).

Quantum numbers (4,3,-2,+½)

n = 4: Principal quantum number = 4.

l = 3: Element has 4f electrons

It is conventional to list quantum numbers in decreasing order.

Hund’s rule states that all the orbitals must be half-filled with electrons having the same spin before any can receive a second electron.

We get the following table:

Element n l mₗ mₛ

La 4 3 3 +½

Ce 4 3 2 +½

Pr 4 3 1 +½

Nd 4 3 0 +½

Pm 4 3 -1 +½

Sm 4 3 -2 +½

The element is samarium, Sm.

Quantum numbers (5,2,-1,-½)

n = 5: Principal quantum number = 5.

l = 2: Element has 5d electrons

We get the following table:

Element n l mₗ mₛ

Y 5 2 2 +½

Zr 5 2 1 +½

Nb 5 2 0 +½

Mo 5 2 -1 +½

Tc 5 2 -2 +½

Ru 5 2 2 -½

Rh 5 2 1 -½

Pd 5 2 0 -½

Ag 5 2 -1 -½

The element is silver, Ag.

Note: These assignments assume that there are no exceptions in the Periodic Table.

7 0

3 years ago

During prophase, which of the following events

alexdok [17]

Answer:

Spindle fibers form.

DNA condenses into chromosomes.

Explanation:

Prophase is the first stage of mitosis. Mitosis produces 2 daughter cells from a parental cell.

Spindle fibers form - this is true. During prophase, the mitotic spindle forms. Later during mitosis the spindle attaches to the centromere of chromosomes and pulls them to opposite ends of the cell prior to division

DNA condenses into chromosomes. - this is true. In the nucleus during interphase, the DNA is relatively loosely compacted. However, prior to division, the DNA is condensed into structures called chromosomes which are then paired up and distributed to the daughter cell.

Chromosomes move to opposite ends of the cell. - this is false. This happens during anaphase

Nuclear membrane begins to re-form. - this is false. This happens during telophase.

7 0

3 years ago

Balance the equation below for the reaction between hydrogen and chlorine, using the smallest whole-number

Elanso [62]

H2(g) + Cl2(g) = 2 HCl(aq) (balanced equation)
1, 1, 2 (coefficients)

3 0

3 years ago

Help please! please answer with a good answer

KonstantinChe [14]

Answer:

what the heck what is that?

Explanation:

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3 years ago

As Mia mixed two substances in a test tube, she noticed that the test tube became warm. She also noticed gas coming from the tes

ss7ja [257]

Answer:

a new substance was forming

Explanation:

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3 years ago